1. Field of the Invention
The present invention relates to a method for manufacturing an organic thin film transistor substrate and, more particularly, to a method for manufacturing an organic thin film transistor substrate of a bottom gate type.
2. Description of the Related Art
Generally, a liquid crystal display (LCD) device displays image by controlling the transmittance of light generated from a backlight unit. Light transmittance is controlled by the rotation of liquid crystal molecules in response to a changing data voltage applied to pixels arranged in a matrix shape on the LCD panel. A thin film transistor (TFT) is used as a switching element for supplying a pixel signal and as driving element for each of the liquid crystal cells. The TFT has a semiconductor layer that includes a channel region formed between a source region and a drain region, a gate electrode formed in a region corresponding to the semiconductor layer, an insulating layer for insulating the gate electrode from the semiconductor layer, and source and drain electrodes. An organic TFT has an organic semiconductor layer. The organic semiconductor material may be formed through a low temperature process and may be used on a plastic substrate. The organic TFT is formed through patterning using a thin film depositing (coating) process, a photolithography process and an etching process.
During the photolithography process and the etching process, the organic semiconductor material may be exposed to chemicals such as an etchant of a strong acid that may damage a layer that insulates the gate electrode. Particularly, metal etchants may be absorbed through the surface of the gate insulating layer and adversely affect the electrical characteristics of the organic thin film transistor.